Ear-shaped ring travelers for yarn twisters

ABSTRACT

A generally ear-shaped ring traveler, designed for movement with minimized ring to traveler friction and aerodynamic resistance along the inside of a ring of a yarn twister or like machine, is disclosed. The cross-sectional configuration of the traveler at any given transverse plane is characterized by an oblong shape having a relatively wider or blunt leading edge and a relatively narrower or less blunt trailing edge, with the cross-section being airfoil-shaped in the main body section and in each of the upper and lower transverse arms so as to cause lift forces opposing the yarn forces and the centrifugal force to be generated, and generally drop-shaped in the transition regions between the arms and the main body section so as to provide a generally neutral streamlining effect. This abstract is not to be taken either as a complete exposition or as a limitation of the present invention, however, the full nature and extent of the invention being discernible only by reference to and from the entire disclosure.

This invention relates to ring travelers for yarn spinning or twistingmachines, and in particular to an ear-shaped traveler designed formovement in a single given direction along the ring of such a machine.

Travelers for ring twisters and like machines are conventionallydesignated as either ear-shaped or C-shaped. By way of definition, anear-shaped traveler is one which in use has a primarily straight mainbody or mid-section extending generally vertically across and travelingalong the inside face of the circular ring, and two end sections or armsextending codirectionally generally transversely to the main bodysection and outwardly therefrom over the top and bottom edges of thering, respectively, with the arms terminating in a pair of inwardlydirected hook-like ends engaging the outside face of the ring to retainthe traveler thereon despite its laterally open construction, and withthe traveler being somewhat recessed at the juncture between the mainbody section and the upper arm thereof to define a guide through whichthe yarn passes as, by virtue of the concurrent uniform up and downmotion of the ring relative to the bobbin, it is helically wound on thebobbin while being at the same time subjected to the desired torsion ortwist. A C-shaped traveler, on the other hand, is one which in use has aprimarily arcuate main body section extending generally horizontallyacross and traveling along the top edge of the ring, the body sectionterminating in two inwardly directed hook-like ends engaging,respectively, under the inner and outer peripheral top edge flanges ofthe ring to retain the traveler on the ring, and the yarn passing underthe said body section on its way to the bobbin.

Merely by way of example, a number of known ear-shaped travelers whichare representative of the various constructions developed over the yearsare disclosed in U.S. Pat. Nos. 631,342 and 1,937,676, and in GermanPat. No. 958,908 and OLS No. 2,224,935.

When such a traveler runs along the ring at high speeds, differentforces act on the traveler. On the one hand, there are the forcesresulting from the tension of the yarn, which forces have componentsdirected horizontally inwardly of the ring, i.e. toward the center orthe axis of the ring, as well as components directed vertically upwardlyrelative to the ring. On the other hand, the traveler is subjected toforces directed radially outwardly of the ring, i.e. the centrifugalforces resulting from the movement of the traveler along the ring. As afunction of the relationship of the forces bearing upon the traveler,therefore, the traveler has predetermined zones facing the ring whichare subject to increased loads and, hence, to greater wear. Moreover,the circular motion of the traveler along the ring takes place against asubstantial air resistance.

It has been proposed in the art (see, for example, U.S. Pat. Nos.2,111,544 and 2,111,545) that the air resistance of a ring traveler maybe reduced essentially by providing the traveler with a cross-sectionalconfiguration which is streamlined with respect to the direction ofmovement of the traveler in such a way that the traveler while in motionbehaves aerodynamically as favorably as possible. To the same end, ithas also been proposed to utilize a cross-sectional configuration whichis either drop-shaped or airfoil-shaped, as shown, for example, in awithdrawn German Patent Application No. Sch 13972 VII/76c, publishedAug. 16, 1956. Still further, it has been proposed (see, for example,U.S. Pat. No. 2,116,071) that the tilting tendency of the travelerresulting from the tension of the yarn may be counteracted by acorresponding distribution of the weight of the traveler in such a waythat the major portion of the weight is provided at one side of thetraveler standing in a predetermined relation to the tension of yarn.

The various prior art constructions so far discussed have, however, notbeen fully satisfactory in terms of maximizing the possible rotationalspeed of movement of the traveler. To enable such an increase in thetraveler speed and a corresponding increase in the operating speed ofring spinning and twisting machines to be attained, I have proposed inmy prior copending application, Ser. No. 451,297, filed Mar. 14, 1974and assigned to the same assignee as the instant application, a basicconstruction for an ear-shaped traveler designed for movement in asingle given direction along the ring, which construction ischaracterized by a cross-sectional configuration which in all essentialtransverse planes has an oblong shape provided with a wider or bluntleading edge and a relatively narrower or less blunt trailing edge. Asdisclosed in the said prior application, within that concept the shapeof the cross-sectional configuration may be airfoil-like, drop-like oreven generally elliptical. Reference may be had to said priorapplication for further details.

The present invention represents a modification of the aforesaid basicconstruction. In particular, it is the object of the present inventionto provide a novel and improved traveler of the type described abovewhich is so constructed that the ring-engaging contact areas of thetraveler which are subject to greater wear under the effects of theforces acting on the traveler, are largely relieved from the forcescausing the pressing of the traveler at such contact areas intoengagement with the ring, so that even in the case of very high runningspeeds and concomitant high forces, there occurs only minor wear and thetraveler moves under an optimally low load.

In accordance with the present invention, these objectives are attainedby a traveler construction characterized (a) in the main body sectionthereof juxtaposed to the inside of the rail, by a lift-generatingcross-sectional configuration that counteracts the effects ofcentrifugal force, and (b) in the two transverse arms above and beneaththe ring by cross-sectional configurations which jointly counteract theeffects of the yarn tension forces. Advantageously, the cross-sectionalconfigurations at least in the transition areas between the main bodysection and the arms of the traveler, and normally also in thetransition sections between the arms and the respective extremities orhook ends of the arms, are designed to be neutral insofar as lift isconcerned but still aerodynamically streamlined. The cross-sectionalconfigurations of the hook ends of the traveler arms engaging the ringon the outside can be designed to be similarly neutral. Advantageously,however, the arm ends will also have cross-sectional configurationsdesigned to generate lift forces directed toward the center of the ring.In all cases, of course, the cross-sectional configuration will have thehereinbefore mentioned oblong shape characterized by a blunt orrelatively wider leading edge (as viewed in the intended direction ofmovement of the traveler) and a less blunt or relatively narrowertrailing edge.

Through the construction of the traveler in accordance with theprinciples of the present invention, those ring-engaging regions of thetraveler which are subjected to the greatest loads, i.e. principally theoutwardly facing inside of the main body section and the upwardly facinginside of the lower arm of the traveler, are optimally relieved from theeffects of friction generated between these regions and the ring, sothat even at very high operating speeds, the traveler has asubstantially longer life. At the same time, the traveler profilesprovided in accordance with the present invention reduce considerablythe air resistance which opposes the movement of the traveler along thering.

The foregoing and other objects, characteristics and advantages of thepresent invention will be more clearly understood from the followingdetailed description thereof when read in conjunction with theaccompanying drawing, in which:

FIG. 1 is a rear elevational view (with respect to its direction ofmovement) of an ear-shaped traveler in accordance with the presentinvention, the traveler being shown in operating relation to a spinningor twisting machine ring (shown in broken lines only);

FIGS. 2 to 6 illustrate the lift-generating profiles or cross-sectionalconfigurations of the main body section, the upper and lower arms, andthe upper and lower hook ends of the traveler; and

FIG. 7 similarly illustrates the neutral profile or cross-sectionalconfiguration of the transition sections between the main body sectionand the arms of the traveler.

Referring now to the drawing in greater detail, the ear-shaped traveler1 shown in FIG. 1 exhibits, as viewed from behind in its direction ofmovement, the profile customary for such travelers. Thus, the traveler 1has a main body section 12, transverse upper and lower arms or endsections 17 and 22, the arms terminating in respective mutually inwardlydirected hook-like ends 31 and 36, respective transition sections 26aand 26b between the main body section and the arms 17 and 22, andrespective transition sections 26c and 26d between the arms and the hookends 31 and 36. At the juncture of the main body section 12 and theupper arm 17, the traveler is formed with an arcuate recessed region todefine the guide space through which the yarn to be twisted will pass.When the traveler is in use, the main body section of the travelerextends generally vertically across and moves translationally along theradially inner face of the ring 2 (shown in phantom outline only). Atthe same time, the upper and lower arms extend generally horizontallyacross and move translationally along the upper and lower edges,respectively, of the ring, and the hook-like ends extend in over andmove translationally along the ring at the outside face thereof andprevent the traveler from falling off the ring. In FIG. 1, it will beunderstood, the center of the ring 2 is situated to the right-hand sideof the traveler.

In FIG. 1, the three regions 4, 5 and 6 of the traveler that areparticularly subject to wear are denoted by dot-dash lines. Of these,the region 4 is the inside surface of the main body section 12 which, asa result of centrifugal force, indicated by the double-line arrow 11,acting upon the traveler 1 when the same is moving at a high speed, ispressed against the inside face of the ring 2. The region 5 is theinside surface of the recessed transition section between the main bodysection 12 and the upper arm 17, against which surface the yarn 7 rubswhile being guided, essentially under a tension indicated by thedouble-line arrow 8, to the bobbin or taken-up spool (not shown).Because of the tension on the yarn, there is exerted onto the traveler aforce having a component 9 directed toward the center of the ring and acomponent 10 directed upwardly relative to the ring. The region 6 is theinside surface of the lower arm 22 where the traveler, under a forceindicated by the double-line arrow 21, tends to be pulled against and torub frictionally along the bottom edge of the ring by the raising of thetraveler under the effect of the component 10 of the yarn force.

It will be seen that, as an abstract proposition, the yarn forcecomponent 9, being directed oppositely to the centrifugal force 11, iscapable of partially counteracting the effects of centrifugal force. Inpractice, however, since by virtue of the location of the transitionsection 26a, the yarn exerts a tilting moment on the traveler (in theclockwise direction in FIG. 1), the contact, and hence the friction,between the traveler and the ring both in the region 6 of the lower armand in the lower part of the region 4 of the main body section isintensified, the effects of which are sufficiently adverse as to negateat least partially the benefits resulting from the opposition betweenthe forces 9 and 11.

The indicated loads and forces 8 (10), 11 and 21 nevertheless aresuccessfully counteracted in substantial measure through a specialdesign, in accordance with the present invention, of the cross-sectionalconfigurations of the various sections of the traveler 1.

For this purpose, the main body section 12 is provided with alift-generating profile or cross-sectional configuration, designated 12ain FIG. 2, which is generally oblong, and more particularlyairfoil-like, in shape and has a relatively wider or blunt end 14 at theleading edge of the section (as viewed with respect to the direction ofmovement 15 of the traveler along the ring) and a relatively narrower orless blunt end 13 at the trailing edge of the section. As a result,there is generated in this region of the traveler a lift or buoyancyforce 16 tending to displace the traveler radially inwardly of and thusoff the inside face of the ring. Correspondingly, the two transversearms 17 and 22 extending, respectively, over and under the ring 2 alsohave a lift-generating profile or cross-sectional configuration,designated 17a and 22a in FIGS. 3 and 4, which is generally oblong, andmore particularly airfoil-like, in shape and has in the one case a moreblunt leading edge 18 and a less blunt trailing edge 19, and in theother case a more blunt leading edge 25 and a less blunt trailing edge24. Both of these profiles are similarly oriented so that, with respectto the direction of movement 15, the upper arm generates a downwardlydirected lift force designated by the arrow 20, while the lower armgenerates a downwardly directed lift force designated by the arrow 23.Both of these forces thus are directed counter to the yarn forcecomponent 10, so that the combined lift generated by the two armssubstantially relieves the region 6 of the lower arm from the retardingeffects of friction at the underside of the ring. As shown, thecross-sectional configuration 22a of the lower arm may be smaller thanthe cross-sectional configuration 17a of the upper arm.

The transition sections of the travelers, by way of contrast to the mainbody section 12 and the arms 17 and 22, can have any profile orcross-sectional configuration that is aerodynamically favorable, i.e.streamlined, but is neutral as far as lift generation is concerned. Sucha construction is illustrated in FIG. 7 which, in the first instance,shows the cross-sectional configuration of the transitional section 26abetween the body section 12 and the upper arm 17. As before, thecross-sectional configuration is generally oblong in shape and has amore blunt leading edge 29 and a less blunt trailing edge 30, but itsparticular shape is now drop-like and essentially symmetrical withrespect to a longitudinal dividing line designated by the dot-dash line28. As indicated by the numerals in parentheses, the other transitionsections 26b, 26c and 26d of the traveler can, and normally will, havethe same drop-shaped profile, but it will be understood that thecross-sectional configuration of any given transition section can differin size and shape from the one illustrated in FIG. 7, if such adifference is dictated by the cross-sectional configurations of therespective adjoining sections of the traveler. The only invariablerequirement for the transition sections is that, apart from beingstreamlined, i.e. as aerodynamically favorable as possible, they shouldbe neutral insofar as lift generation is concerned.

In like manner, the hook ends or arm extremities 31 and 36 which engagethe ring 2 at the outside may have a profile or cross-sectionalconfiguration which is drop-shaped and hence neutral. As shown in FIGS.5 and 6, however, the cross-sectional configurations, designated 31a and36a, of the arm extremities or hook ends may be, and preferably are,airfoil-shaped so as to be able to generate codirectional lift forces,indicated by the arrows 34 and 38, which would be added to andsupplement the lift force 16 generated by the main body section 12 ofthe traveler. In either case, of course, the cross-sectionalconfigurations of the hook ends will be generally oblong in shape with arelatively wider or blunt leading edge, designated 32 in FIG. 5 and 37in FIG. 6, and a relatively narrower or less blunt trailing edge,designated 33 in FIG. 5 and 39 in FIG. 6.

As a further refinement of the traveler construction in accordance withthe present invention, the main body section thereof can also be made insuch a way that the lift force generated thereby and directed toward thecenter of the ring 2 will be greater in the lower region of the travelerthan in its upper region, thereby to provide as well an effectivecounteraction to the tilting moment generated by the yarn tension. Atall times, of course, care must be taken that the lift forces 20 and 23remain effective to counter the vertical component 10 of the yarntension.

It will be understood that the foregoing description of preferredembodiments of the present invention is for purposes of illustrationonly, and that the various structural and operational features andrelationships herein disclosed are susceptible to a number ofmodifications and changes none of which entails any departure from thespirit and scope of the present invention as defined in the heretoappended claims. Thus, the extent of asymmetry of the airfoil-shapedcross-sectional configurations with respect to the respectivelongitudinal dividing lines thereof shown in FIGS. 2 to 6 may be variedas desired as long as the larger parts of the sections 12a, 31a and 36aface inwardly of the ring and the larger parts of the sections 17a and22a face downwardly of the ring. Also, although the longitudinaldividing lines of the various sections are shown as being oriented inthe direction of movement, the sections could be constructed so as toprovide for a suitable angle of attack other than 0°.

What is claimed is:
 1. An ear-shaped ring traveler designed for movement in only one given direction along a ring of a yarn twister or like machine,a. said traveler having a main body section, first and second transition sections at the opposite ends of said main body section, respectively, first and second arms extending generally codirectionally from said first and second transition sections, respectively, third and fourth transition sections at the ends of said first and second arms remote from said main body section, respectively, and first and second hook-like ends extending mutually inwardly toward one another from said third and fourth transition sections, respectively, b. of which, when the traveler is in use, said main body section extends generally vertically across and moves translationally along the inside face of the ring, said first and second arms extend generally horizontally outwardly across and move translationally along the upper and lower edges of the ring, respectively, said first and second hook-like ends extend downwardly and upwardly, respectively, over and move translationally along the outside face of the ring, and said first transition section at its inside surface defines a guide for the yarn being twisted, c. said traveler having aerodynamically streamlined cross-sectional contours throughout, d. the cross-sectional configuration of any part of said traveler on a transverse plane perpendicular to the longitudinal dimension of the respective part being generally oblong in shape and having, as viewed with reference to said given direction of movement, a relatively blunt leading edge and a relatively less blunt trailing edge, e. said cross-sectional configuration of said main body section being airfoil-shaped and oriented, with reference to said given direction of movement, so as to generate, when the traveler is in use, a lift force directed oppositely to and counteracting the centrifugal forces exerted on said traveler, thereby to urge said main body section out of frictional engagement with the inside face of the ring, and f. said cross-sectional configuration of each of said arms being airfoil-shaped and oriented, with reference to said given direction of movement, so as to generate respective codirectional lift forces directed downwardly with respect to the ring oppositely to and counteracting the upward component of the yarn force, thereby to urge said lower arm out of frictional engagement with the lower edge of the ring.
 2. A traveler as claimed in claim 1, wherein each of said airfoil-shaped configurations is asymmetrical with respect to a respective longitudinal dividing line extending from said leading edge to said trailing edge, with the larger part of said cross-sectional configuration of said main body section being located to the side of the respective longitudinal dividing line facing toward the middle of the ring when the traveler is in use, with the larger part of said cross-sectional configuration of said first arm being located to the side of the respective longitudinal dividing line facing toward the upper edge of the ring, and with the larger part of said cross-sectional configuration of said second arm being located to the side of the respective longitudinal dividing line facing away from the lower edge of the ring.
 3. A traveler as claimed in claim 1, wherein the cross-sectional configurations of at least said first and second transition sections are neutral with respect to generation of lift forces.
 4. A traveler as claimed in claim 1, wherein the cross-sectional configurations of said transition sections are neutral with respect to generation of lift forces.
 5. A traveler as claimed in claim 1, wherein the cross-sectional configuration of each of said transition sections is drop-shaped and symmetrical with respect to a longitudinal dividing line extending from said leading edge to said trailing edge.
 6. A traveler as claimed in claim 1, wherein the cross-sectional configuration of each of said hook-like ends is airfoil-shaped and oriented, with reference to said given direction of movement, so as to generate, when the traveler is in use, respective codirectional lift forces directed inwardly of the ring and supplementing said lift force generated by said main body section in opposing the effects of centrifugal force.
 7. A traveler as claimed in claim 1, wherein the cross-sectional configuration of each of said hook-like ends is neutral with respect to generation of lift forces.
 8. A traveler as claimed in claim 1, wherein the cross-sectional configuration of each of said hook-like ends is drop-shaped and symmetrical with respect to a longitudinal dividing line extending from said leading edge to said trailing edge.
 9. A traveler as claimed in claim 1, wherein said airfoil-shaped cross-sectional configuration of said main body section in the lower half thereof is designed to generate a greater lift force than said airfoil-shaped cross-sectional configuration of said main body section in the upper half thereof, thereby to counteract the tilting moment exerted on the traveler by the yarn. 